Document mmOQ40xqOGZEmdBB7D89NGDeb

FILE NAME: Z< DATE: : DOC#: Z< DOCUMENT DESCRIPTION DZZE/K^,DZZ ^ZZZ ~~m~l Johns-Manville Interna~ Correspondence To: Paul Kotin, M. D. From: George W. Wright, M. D. D~le: July 23, 1975 Copies: file & C SUDiect: MEETING 'ORGANIZED BY DR. JOHN FIID(LEA OF NIOSH TO CONSIDER, A REPORT BY DR. SELIKOFF AND HIS ASSOCIATES ON THEIR PRELIMINARY FINDINGS WITH RESPECT TO THE ENVIRONMENT AND THE HEALTH OF WORKERS EMPLOYED IN THE REPLACEMENT OF BRAl<E LININGS. The meeting was held in the afternoon of' July 21, and those attending are indicated on the attache~ exhibit. The agenda is also attached. Dr. Selikoff opened the meeting by stating that their interest in the health of brake lining repair workers arose because of a report of several cases of mesothelioma occurring in auto repair workers. There was some confusion in my mind at first as to whether this was solely from the New York area or a larger popUlation. It later developed that there were 4 and possibly 5 cases that had come to his attention from workeJ:;s in this trade throughout the ' United states. He estimated that at least one million men might be thus employed and exposed to asbestos. He repeated several times that in his judgement it was not possible at ,this point in the development of information to say whether or not this represented an excess risk of mesothelioma but that he thought the observation merited further exploration. He also indicated that he had reviewed this problem '-lith appropriate people at the Ford Motor Company. ',He then asked Dr. Langer to discuss the nature of the material found in the dust that accumulates in brake .. drums and which is by cusl:.omary practice blovm off the surface and into the surrounding air at the time that work on the brake drums is being carried out. Lang~r opened his comments by saying that others had reported thrlt 30 percent of the asbestos in brake lining is cqnvGrted by high heat to Forsterite. He indicated that "modifiers" present prevented the fonnation of ForstGrite and he hus found Forsterite in brake drl@ dust only in one instance. The only person I know of who says that the asbestos is converted to Forsterite is Paul Gross. Others say that it is converted to an amorphous and essentially non-fibrous material. Dr. Langer indicated that the residue was not pristine chrysot.i.le fiber but he did rot speak about' arnorphoua material. Langer, in addition, said that he Paul Kotio, M. D. July 23, 1975 Page #2 found pure asbestos fibers. This too has been reported by others in quantities of anything from 1 to 3 percent of the residual dust. He then asked Dr. Rohl to disc.uss the fiber counts in the dust that was obtained. It should be indicated that brake drum dust was obtained from cars in taxi repair shops, municipal bus repair shops and I believe some other similar workplaces. Dr. Rohl indicated that studies of the material blown from, or obtained from the brake drum contained fibers in large numbers and these were chrysotile. None of the fibers were more than 0.5 microns long and the bulk were under 0.3 microns. In diameter they varied from 250 to 500 angstroms. On the other hand, he reporterl that the fiber count varied from 0.4 to,29.0 fibers per ml at the worker breathing zone level where brakes were being cleaned by air jet. It was my understanding that these were fibers that were countable under the OSHA. regulations and therefore would be visible with the light microscope and longer than 5 microns. It was not entirely clear to me whether these optically recognizable fibers actually came from the brake drum dust or not. If they did. I have a conflict in reconciling his electron microscope study with his light microscope studies. Rohl also reported that in brushing the brake drums rather than blo\.ring them off the fiber coun~ (OSHA criteria) varied from 1 to 4 per ml, during grinding the fiber count varied between 1 and 5. Most important . was the finding that when men were bevcllirgthe brake linings by grinding the counts varied between 20 and 75 fibers per ml. During punching, riveting or sweeping the fiber count varied between 2 and 4 fibers per ml. It is my understanding thilt other kinds of grinding of the brake lining goes on in the fitting process. Ed Fenner tells me that they do something called "arcing" and this involves direct grinding of the brake lining and is a very dusty job. Rohl also showed <:lata to indicate that there WQS a very rapid fall off in the level of count:: as one moved away from the .source so that fiber counts 10 or 20 feet more away from . the source of origin were lower than 1 fiber per ml and in general were in the neighborhood of 0.2. .On some questioning it developed that these shops were what would be considered to be very well 'run and therefore tend to have lower dust counts than would the average smaller shop. In the pictu,res that v/ere shown and the comrnGnts that were made ther~ was no evidence to indicate th~t any sort of dust exhaust or. suppression systems were in use. I was surprised that no direct referrence to extensive data relative to brake drwn dust by Lynch, by Jacko et ai, by Anderson et aI, and by Johns-Hanville as well as a small study of the work place during brake maintenance by Hickish and Knight was not made by. eitller Langer or Rohl. Paul Kotin, M. D. July 23, 1975 Page #3 At the request of the Unions Dr. Selikoff also did a preliminary examination of 104 workers currently emp- loyed in the The men were places where, the dust counts not selected on the basis of had been duration made. or intensity of exposure, some working only once a week they would be exposed to brake lining operatiG>Os but where, the majority of them had worked for between 10 and 20 years. Of the 104, 29 had no direct exposure to asbestos or pul- monary disease but worked in the same area. The data was presented so rapidly that I could not follow all of it but in part at least it is as follows: Of the 64 men' kwneorwenretoadhaavsecdatiergeocrtysh"ospoerxtp"ossumreal1l6irhraedgcuhlaerstdfeinlmsistieths at , with a profusion of 1/0 or more. No ing were spoken of and I assume that controls for the readthese were read on one occasion by one person. The inference was that these TrehaedreingWsaScnoonsbtrietauktdeodwn"doisfehaoswe" maanttyrihbaudtapbrolefutsoionthereaedxipnogssure. in excess of 1/0 and thus I have no knowledge about the extent of the changes. Later in 'the meeting I question of the interpretation of this kind of raised the information. In the absence of controls, there is no way to estimate the influence of bias in that the re.:tder knew the fthilimss kcinamdeoffrormeadaningex. poIsetdisgrooubpvious and the tendency thing in the way under of an these circumst<.lnces is abnormality. The best to find someway to count- eract among this hias is to have a group of control.s dispersed ' the exposed group and have the entire set read "blind" In the absence of this there are two other ways of going at it, neither of which were utilized in these readings. The first of these is to have several readers look at the films independently. that has the majority The accepted reading is then of the readers designation. the For one example. if the majority of the readers class a film as a 1/1 and used is a minor.ity 1/1. Some classify it use reading as by a 0/1 the ultimate reading "consensus" but this is a poor and unacceptable method dominant., reader who is able to because usually there is one persuadG the others as to what he 'thinks it is. The other way of going at it is to know what the exposure history is and be able to rank the observed popUlation interms of intensity of exposure. The films are l:hen read with no knowledge of the intensity of the exposure and the distribution of less bias than otherwise because the reildings has slightly least exposure serves 'as a control for the more heavily exposed. This not as good ~s having mUltiple readers or actual mGthod is control films interspc?rsed amongst the films of the popUlation under study. to interpret With their the information I have I don't know how x-ray findings other than to say that the inference that canefrom them was that all 16 of these Paul July RotinA M. 23, 1'::175 D. Page #4 individuals h~d disease. The UICC classification is not a diagnostic classification in any sense of the word and serves only an epidemiological purpose. I know of no basis on which one can conclude that people with a read- ing of 1/0 have actual disease. Additional data was pre- sented along- the lines of pulmonary function l}'teasurements. The da-ta showed a substantial percentage of those who were directly exposed to have what was called restrictive disease. I don't know what criteria were used for arriving at this designation and hence can't evaluate the finding. If it was based on actually measured total lung volumes, rather than just on vital capacity, then the data }:las useful meaning. The strong suggestion made by the Sinai group was that in these 104 individuals they had demonstrated the presence of asbestos related diseaSE:. Haybe this was not their intention but in contrast to Dr. Selikoff's statement that 4 cases of mesothelioma did not constitute sufficient evidence to incrim,:i.nate the, exposure, nothing \"as said to tIle effect that the x-ray and pulmonary function measurements may not have been very sound evidence of disease. On'the basis of these reports from Dr. Selikoff's laboratory sevoral suggestions were forthcoming.- First of all thece was an inference that Langer's studies had a strorg implication that a public health hazard might exist. At the very least the implication both from Langer and from Rohl \-,as that _the short fibers found in large numbers in the dust from the brake lining posed a potential threat to health of great magnitude. In my comments I pointed out that there was growing experimental. evidence that fibers of lengths under- 10 micron did not produce disease in terms of pulmonary fibrosis and very likely did nol:. produce mesotheliolll<1. On this basis I would think the presence of the very short fibers has little or no biological significance uncil proven otherwise. The longer fibers are quite another matter since they are capable of producing asbestos associated biological effects. In my comments I stated 'that the o'bsL~rvation showing fiber concentrations of 20 to 70 fibers per millilitar in the bevelling operation did not surprise mc. In other settings, the grinding of the surface of new brake lining is a kno\Yn quite dusty process. Depending upon the accwnula tad duration of e:<posure in this k.ind .of oporation one had every reason 1.:0 expect that in those \Yho have been doing'this for a sub:3tantial length of time there would be a risk of pulmonary fibrosis and the other kinds of asbestos associated diseuse. Even though this might occur only once or twice a \Yeek, these high intermittent e:<posures might have an adverse effect. Since no data in UH~ way of cummulated dosage was presented there is no way in \vhich the risk can be evaluated. It WClS (Juite clear that the Union representatives QXp8ct:a study of this cate<jJory of workers t:o be made by Paul Rotin, N. D. July 23, 1975 Page #5 Dr. Selikoff's group. Mr. Cefalo of the Machinists Union made the blunt. statement that if funds were not available he could promise that they could become available. Whether this. meant from Union sources or from the influence of the Unions on the Government was not clearly stated As you know I had to leave before the me~ting ended and I don't know what the upshot of the matter was. I asked myself the question; what is to be gained by mounting a complete epidemiologic study based on observation of these workers and the environment of th(:!ir workplace. If the question is solely whether or not asbestos has the propensity to produce a biological reaction along the lines we already l'.now I would say that making this study would be a very poor use of Dr. Selikoff's and his coworkers time and of expenditure of tax payers money. We already have that kind of information and nothing in the presentation of the afternoon indicated that the exposure in this group was appreciably different from that which has been reported in other occupational groups. If adequate information cnn be obtained then two questions might be approached. 'rhere is the implication fostered primarily by Dr. Selikoff's group that short asbestos fibers 5 J.l long) produce all of the known biological eff'~cts in workers substantially exposed. They have taken this attitude on the basis prima~ily that short fibers are found in the lungs at autopsy and therefore must be the cause of the disease. On the basis of animal experimentation others do not accept the hypothesis that fibers shorter than 5 to 10 microns in length have biological capacity. There appears to b~ a reluctance on the part of the Selikoff group to accept the inferences of the experilTlental animal data. The difficulty of looking to human exposure for resolution of the question is obvious. rI'hose groups exposed ocupa t.ionally, at least in studies up to the present, are exposed to a mixture of long and short. fibers and there is thus no way of separating the affects of short versus those caused by long fiber. Not even autopsy data will help in this respect since long fibers .are subject to shortening by fracture vlith a passage of time. If a group exposed only to the dust from the braJ(e drums as described by Langer and Rohl cou~d be separated out and looked at in terms of their mortality and morbidity experience then a study of the brake lining workers population would be emmincntly ....,orth while. If this cannot be dOPG and the exposures are mixed, the population will be of no use for examining the effects of short fibcrs versus long fibors. l\nother question might be looked at by studying this gl'C)up. There still remains Cl question in the minds of some as to whether or not the 2 fiber per cc level in the ambient air (OSHA standard) is adequate to protect the worker!'> who are exposed throughout a lifetime. If Dr. Selikoff's group can reconstruct.thc exposure histories of these workers in a manner that will give a ranking of Paul Kotin, N. D. July 23, 1975 Page #6 the workers in terms of intensity and duration of exposure then a study of the relationship between this ranking 'arid the biological effects would be useful. If this cannot be done and if the population cannot be divided into those exposed solely to short fibers and those exposed to either solely long fibers or a combination of short and long fibers then I see nothing to be learned from an extensive study of this population that is not already knolm. To be sure, the employees in this trade might want an assessment of ~he potential hazards and this kind of information might be used in persuading both the employers and employees to create a safe work place. I think this ,can be done by utilizing knowledge already existing with respect to biological effects and relai:ing it to a thorough survey of the enviromnent with respect to the level of asbestos fibers in the various kinds of jobs being done in this category of employment. It seems to me that Dr. Selik6ff's group constitutes a resource that: should husband its time and facilities. I would hope they would not embark on a study except in those areas where something useful could be obtained. I think that Cl. thorough investigation into the environment could be thought of as useful study on the basis of what is nO\"l known. In fact, under the regulations set forth by. OSHA the employers should already have developed that information. 'rhe regulations require that when employees, handle materials in processes through which they might be exposed to the inhalation of asbestos fibcrs certain environrnental and physical examination requirements must be satisfied. I '~lOuld think this would be the most useful avenue to pursue' since the requirements under OSHA are quite clear cut. I don't know at this time what can be anticipated in the WiJ.y of reconstructing exposure histories or in dividing the population into the tl-vo groups with the respect to length of fiber. On the basis of past experience I would not be very hopeful that this could be accomplished with a degree of accuracy permitting any conclusions from 11 biological survey to' be dra\'In. Several other points arose from this meeting that seemed to rne to be important. First of all, insofar as I can learn, laboling of brake lining n~terials in a way that o,.lOuld in[ol1l1 the lIse'r and the worker of the inherent hazarB re lai:E;d to the various ways in which thE) rna tcrial might be handled has not been a common practice if done at all. I would hope this would be corr0cted at once. Hr. Sam M~')yers of the United Auto Workcl..-s Local 259, showed posters his group have developed, warnin<;J of the passible effects of br.ake lining handling on hCLllth. He also made c:J!1structivQ rG'marks during the meeting. It GeemB clear t.hat scme m0chanism must be found for alerting all workers in this truJo to the potential hazards and tlm need to join Paul Kotin. M. D. July.23, 1975 Page -:if? with the employers in finding ways to work safely. An educational program through the Unions 'as well as the employers should be mounted as quickly as possible. Since this trade may involve only a few people in a given place and preswnably is not totally uinionized I believe this mlly be a ma t;ter of considerable magnitude. 'Yhe di scussions of this particular afternoon demonstrate as well as anything I know the obligation on,the part of manufacturers to know where their products containing potentially toxic material go and' the way in which they are used. In those circum- stances where a hazard can be created by the use of the product a means of informing the worker must be found. At the very least this should be labelling and in all pro- bability it should be a joint educational effort on the part of the workers organizations and the empJ.oyers and the pro- ducers. Unfortunately labelling is ofton times either' ignored or loses its impact with the passage of time. For this reason more persistent and active methods should be found for accomplishing the purpose. In view of the nature of the problem and the fact that the current OSHA regu- lations should have brought. it to the fore I was surprised that no revresentative of OSHA was present. Representatives of EPA were present even though their concern 'MJuld be expected to be less at this point than should be true for OSHA. . I regret: that I was unable to attend the meeting beyond 3:40. I will call Dr. Finklea and see if he can give me more information and if so I will transmit this to you. \vright I M. D.